ML20009D089
| ML20009D089 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/08/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8107230121 | |
| Download: ML20009D089 (9) | |
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Docket Hos.: 50-327/328 f,g 4, h' [t p
fir. H. G. Parris
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b tanager of Power Tennessee Valley Authority
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500A Chestnut Street, Tower II p
Chattanooga, Tennessee 37401
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Dear fir. Parris:
SUBJECT:
REQUESTS FOR INFORilATIOk ON liVDROGEN CONTROL Enclosed are requests for additional information on hydrogen control that is needed by October 1,1981 in order to meet the license condition of January 31, 1982.
The enclosure has been sent to Duke ana AEP for responses on their ice condenser plants. We suggest that you coordinate your efforts with the other participants in the research program on hydrogen combustion and control to eliminate any duplication of effort.
Sincerely.
Original signed by Robot 1AM.'"
Robert L. Tedesco, Assistant Director for Licensing Division of Licensing
Enclosure:
As.tated cc:
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1.
Describe the permanent hydrogen igniter system installed inside contain-ment.
Provide and justify the criteria used for the system design.
In-clude in your discussion the proposed surveillance testing, and technical specificati'ons for the permanent system.
2.
List the rooms within containment for which there is no direct coverage by igniters and justify-exclusion of these regions.
3.
Discuss the effects of igniter operation in lean (0-4 v/o) hydrogen mix-tures. for sustained durations (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) on the ability of the igniter to
. subsequently perform its intended function.
Describe the testing performed to evaluate the. temperature effects of surface recombination and possible igniter degradation.
c 4.
Provide a complete discussion of the accident symptoms which will result in actuation of the igniter system.
Considering a spectrum of accidents, iden-
'tify the minimum time period in which actuation is required.
Identify and justify the mode of actuation, i.e.., automatic or remote manual.
5.
With ' regard to the Fenwal igniter test program pro /ide the following infor-mation:
a)
Summary of the, data from the Phase 2 Fenwal tests in a format similar to that provided for the Phase 1 tests in the TVA Core Degradation Program Report, Vol. 2.
Include the calculated aP/aP max value.
b)
Description and justification of the scaling of the spray flow tests' l
to the ice condenser upper or lower cc,mpartment sprays.
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c)
Description and justification of the scaling of the steam-hydrogen l
transient injection tests.
i ENCLOSURE
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a Submit a topical report on the CLASIX code; in this. regard:
6.
Describe in detail the version of the CLASIX code used to perform a) the. revised analyses, including a discussi'on of models, methods for
.a solution, assumptions and input parameters.'
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Describe the efforts and results to verify the revised CLASIX code, b)
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Providecomparativeanal.ysestoshowtheeffectsofmodelchanges i) from the initi'al version as. described in the TVA, Core Degr As a' minimum comparative calculations Program Report, Vol. 2.
should be provided to isolate and identify the effects of adding heat sinks, upper plenum volume, fan head characteristics.
Quantify the effects of incorporating the radiation heat tra lI ii) model and describe the results mf analyses to verify this m
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in its application to containment heat transfer.
Provide a discussion of the program to verify the revised C iii)
In-code against other containment codes and experimenbl data.
data.
clude a discussion of both the Fenwal and EPRI hydrogen tes of hydrogen combustion tests Comparison of CLASIX prediction should also describe the code input parameters where us may affect the comparison.
Discuss the treatment of nydrogen addition to a volume c) tion is calculated to oe taking p; ace.
t Discuss in deta'l the treatment of the interme f
d)
'the effect of the doors functioning as check valves on uppe Discuss modeling of burning and downward flame propagation.
WiGA>W w ad the doors.
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Provide the results of calculations to determine the sensitivity to selection of timestep sizes.
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f)
Discuss initialization of the CLASIX code with results of LOTIC 1 analysis; i)
Discuss application of LOTIC 1 to small break analysis especially prior to fan operation or for breaks without fan operation.
ii) Discuss use of LOTIC 1 for analysis of superheated atmosphere conditions.
g)
Provide the results of analysis to identify the effectiveness of the ice bed in removing heat from a Fighly superheated steam-air-hydro-gen mixture.
Provide figures showing ice bed heat transfer coefi-ficients, flow rates.
h)
Discuss the potentia 5 for preferential flow to the ice bed (maldis-tribution) during various accidents.
What is the probability. and con-sequence of the break release point being adjacent to the lower doors with the hydrogen-steam release jetting into 1 or 2 bays of the ice condenser rather than uniformly mixing in the lower compartment.
Discuss the porsible effects of partitioning the ice bed model in the circumferential direction as well as modeling the lower compart-ment as several subvolumes.
i)
Describe any plans for future modification of the CLASIX code.
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4 Provide a discussion of the results of analyses of the 5 0 transient 2
7.
using the revised CLASIX code as discussed above addressing the follow-Y 2
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.ing; Identify and providepe results of a base case reference analysis a) and discuss the rationale for selection of the base case, e.g., re-Provide presentation of a best estimate.ar bounding calculation.
The results justification for'the characterszation of this analysis.
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.clude plots of pressure, temperature and gas concentrations for the various regions of the containment.
b)
Provide the results of sensitivity studies to determine the effect of operation of 1 or 2 trains of2 fans and sprays.
Provide the results of analyses to determine the effect of various c) hydrogen combustion assumptions considering the following:
combustion of lean hydrogen mixtures with, partial comLustion; i) ii) complete combustion of hydrogen at various setpoints; iii) the use of differen't combustion assumptions in separate re-gions of t'e containment; combustion of hydrogen assuming various flame speeds; identify iv) a best estimate and bounding value for flame speeds; and v) simultaneous ignition at multiple igniter sites.
Identify periods in the transier. where hydrogen combustion is limited d) or precicded by the quantity of oxygen available in the compartment.
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/~ Identify the analysis (es) to be used as the basis for determining i
e)
Provide the maximum temperature response of essential equipment.
l justification for the case (s) selected.
Where pressure effects are a major consideration in determining the f) identify survivability of (quipment, such as the air return fanc, and justify the' analysis used as the basis for assuring the equip-ment will function as intended.
.onsidering the capability of the containment shell, crane wall, and g) the operating deck perform an analysis to determine the maximum con centration of hydrogen which could be tolerated to burn to completion in the upper compartment considerir multiple ignition sites and ap-
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propriate flame speeds.
Since the original S D transient analyses did not mechanistically h) 2 consider tennination of the accident it is necessary to identify the Therefore, either demonstrate that'various effects of core recovery.
modes of core recovery do not adversely affect the hydrogen and ste release rates and therefor the containment pressure and temperature response or provide the results of analyses which address the more likely scenarios involving core recovery.
In order to Provide the fan head curve used in the CLASIX model.
i) demonstrate the effects of "t.riable fan flow provide figures of fa flow as a function of time.
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_ i 8.
Identify the spectrum of accidents which you have considered in your evalu-ation of the distributed ignition system.
Discuss the rationale for selec-tion of the various accidents.
Discuss the basis for assumptions regarding A
termination of the accident pricF to core slump if applicable.
Provide the assumptions and results ofdLASb analyses performed to evaluate the contain-ment atmosphere pressure an'd temperature results, similar to that provided for the S D transient, for the various accident sequences selected.
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9.
Prus'de a quantitative evaluation of the probability and effects of form-This evalu-ing a fog, comprised of water droplets, inside containment.
ation should address the following items:
a)
Identification of the range of droplet sizes and requisite volumetric y '
density to preclude combustion of hydrogen or affect combustion char-acte ristics such as flame propagation.
Provide the basis, including experimental evidence, to support these conclusions.
b)
Consideration 'f the probability and consequences of fog forr.ation in the various regions of the containment (e.g., lower compartment, ice condenser).
Provide a quantitative evaluation of the probability.and effects of pro-10.
ducing supersaturated steam conditions in the various containment compart-Discuss the effects these conditions may have on igniter verformance.
ments.
Reference any test data used to support your conclusions.
The utility arguments presented to date on the issue of transition to deton-11.
ation in the ice bed appear to be focused about two points:
1)
The upper plenum igniters will burn H -mixtures as they first become 2
flammable, if richer mixtures begin to be formed the flame front will
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propagate downward in the ice bed where sufficient ste to support a flame; and d
i to The geometry of the ice condenser upper plenum is not con uc ve 2) producing detonations.
Please provide any references to supporting test data derived a) 1.
configu'stion which is analogous to the phenomena describ It appears that the argument pr'esented in item 1. relies upon a l
8 b) l Discuss the implications of generally stable horizontal flame.
i localized downward flame propagation and consequential c 1
ll through the ice bed.
'I Discuss the applicability of thE EPRI tests, designed to stud i
c) sition to detonation, to the ice conCanser geometry.
f t Discuss the applicability of EPRI tests designed to stud d) of obstacles to the geometry of an ice condenser plant.
Provide the L/D value appl.icable to the ice condenser e) partment evaluate the acceleration of burns initiated in the which propagate through the ice condenser.
'i ti nu-Provide analysis to address the consequences of continuou Describe the models, -
12.
j aus burning in the ice bed or upper plenum region.
f iton or burning
[f assumptions, and results of analysis to evaluate the decompos Consider the effects of 2-3 dimension of materials in this region.
Address the likelihood m inadvertently supply i
transfer in the process.
oxygen to support combustion' of foam behind the wall pan j
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Describe the testing perfomed to demonstrate that upper plenum igniters will properly' function in an environment of prolcnged hydrogen burning.
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.Describetand justify the criteria pr$d to determifie adequate coverage of
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the ice-condenser upper ple.num region with igniters to insure comb;stion
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while minimizing exhaust of unburnt gas to the upper compartment.
Identify the minimum number of igniters neede~d to accomplish the intended objective.
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